Remove the send/recv structures from dhcpcd context and allocate

on stack as and when required.
Rather than peaking and checking for truncation for receiving,
just allocate a large enough buffer upfront.

1 files changed, 79 insertions, 75 deletions

diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index 5a248486..7f67287c 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -274,10 +274,17 @@ ipv6nd_sendrsprobe(void *arg)
 {
 	struct interface *ifp = arg;
 	struct dhcpcd_ctx *ctx;
-	struct rs_state *state;
-	struct sockaddr_in6 dst;
+	struct rs_state *state = RS_STATE(ifp);
+	struct sockaddr_in6 dst = { .sin6_family = AF_INET6 };
+	struct iovec iov = { .iov_base = state->rs, .iov_len = state->rslen };
+	unsigned char ctl[CMSG_SPACE(sizeof(struct in6_pktinfo))] = { 0 };
+	struct msghdr msg = {
+	    .msg_name = &dst, .msg_namelen = sizeof(dst),
+	    .msg_iov = &iov, .msg_iovlen = 1,
+	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	};
 	struct cmsghdr *cm;
-	struct in6_pktinfo pi;
+	struct in6_pktinfo pi = { .ipi6_ifindex = ifp->index };
 
 	if (ipv6_linklocal(ifp) == NULL) {
 		logdebugx("%s: delaying Router Solicitation for LL address",
@@ -286,8 +293,6 @@ ipv6nd_sendrsprobe(void *arg)
 		return;
 	}
 
-	memset(&dst, 0, sizeof(dst));
-	dst.sin6_family = AF_INET6;
 #ifdef HAVE_SA_LEN
 	dst.sin6_len = sizeof(dst);
 #endif
@@ -297,25 +302,19 @@ ipv6nd_sendrsprobe(void *arg)
 		return;
 	}
 
-	state = RS_STATE(ifp);
 	ctx = ifp->ctx;
-	ctx->sndhdr.msg_name = (void *)&dst;
-	ctx->sndhdr.msg_iov[0].iov_base = state->rs;
-	ctx->sndhdr.msg_iov[0].iov_len = state->rslen;
 
 	/* Set the outbound interface */
-	cm = CMSG_FIRSTHDR(&ctx->sndhdr);
+	cm = CMSG_FIRSTHDR(&msg);
 	if (cm == NULL) /* unlikely */
 		return;
 	cm->cmsg_level = IPPROTO_IPV6;
 	cm->cmsg_type = IPV6_PKTINFO;
 	cm->cmsg_len = CMSG_LEN(sizeof(pi));
-	memset(&pi, 0, sizeof(pi));
-	pi.ipi6_ifindex = ifp->index;
 	memcpy(CMSG_DATA(cm), &pi, sizeof(pi));
 
 	logdebugx("%s: sending Router Solicitation", ifp->name);
-	if (sendmsg(ctx->nd_fd, &ctx->sndhdr, 0) == -1) {
+	if (sendmsg(ctx->nd_fd, &msg, 0) == -1) {
 		logerr(__func__);
 		/* Allow IPv6ND to continue .... at most a few errors
 		 * would be logged.
@@ -341,41 +340,42 @@ ipv6nd_sendadvertisement(void *arg)
 	struct ipv6_addr *ia = arg;
 	struct interface *ifp = ia->iface;
 	struct dhcpcd_ctx *ctx = ifp->ctx;
-	struct sockaddr_in6 dst;
+	struct sockaddr_in6 dst = {
+	    .sin6_family = AF_INET6,
+	    .sin6_scope_id = ifp->index,
+	};
+	struct iovec iov = { .iov_base = ia->na, .iov_len = ia->na_len };
+	unsigned char ctl[CMSG_SPACE(sizeof(struct in6_pktinfo))] = { 0 };
+	struct msghdr msg = {
+	    .msg_name = &dst, .msg_namelen = sizeof(dst),
+	    .msg_iov = &iov, .msg_iovlen = 1,
+	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	};
 	struct cmsghdr *cm;
-	struct in6_pktinfo pi;
+	struct in6_pktinfo pi = { .ipi6_ifindex = ifp->index };
 	const struct rs_state *state = RS_CSTATE(ifp);
 
 	if (state == NULL || ifp->carrier <= LINK_DOWN)
 		goto freeit;
 
-	memset(&dst, 0, sizeof(dst));
-	dst.sin6_family = AF_INET6;
 #ifdef SIN6_LEN
 	dst.sin6_len = sizeof(dst);
 #endif
-	dst.sin6_scope_id = ifp->index;
 	if (inet_pton(AF_INET6, ALLNODES, &dst.sin6_addr) != 1) {
 		logerr(__func__);
 		return;
 	}
 
-	ctx->sndhdr.msg_name = (void *)&dst;
-	ctx->sndhdr.msg_iov[0].iov_base = ia->na;
-	ctx->sndhdr.msg_iov[0].iov_len = ia->na_len;
-
 	/* Set the outbound interface. */
-	cm = CMSG_FIRSTHDR(&ctx->sndhdr);
+	cm = CMSG_FIRSTHDR(&msg);
 	assert(cm != NULL);
 	cm->cmsg_level = IPPROTO_IPV6;
 	cm->cmsg_type = IPV6_PKTINFO;
 	cm->cmsg_len = CMSG_LEN(sizeof(pi));
-	memset(&pi, 0, sizeof(pi));
-	pi.ipi6_ifindex = ifp->index;
 	memcpy(CMSG_DATA(cm), &pi, sizeof(pi));
 
 	logdebugx("%s: sending NA for %s", ifp->name, ia->saddr);
-	if (sendmsg(ctx->nd_fd, &ctx->sndhdr, 0) == -1)
+	if (sendmsg(ctx->nd_fd, &msg, 0) == -1)
 		logerr(__func__);
 
 	if (++ia->na_count < MAX_NEIGHBOR_ADVERTISEMENT) {
@@ -872,8 +872,9 @@ dhcp6_start(__unused struct interface *ifp, __unused enum DH6S init_state)
 #endif
 
 static void
-ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
-    struct icmp6_hdr *icp, size_t len, int hoplimit)
+ipv6nd_handlera(struct dhcpcd_ctx *ctx,
+    const struct sockaddr_in6 *from, const char *sfrom,
+    struct interface *ifp, struct icmp6_hdr *icp, size_t len, int hoplimit)
 {
 	size_t i, olen;
 	struct nd_router_advert *nd_ra;
@@ -895,33 +896,29 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 
 	if (ifp == NULL) {
 #ifdef DEBUG_RS
-		logdebugx("RA for unexpected interface from %s",
-		    ctx->sfrom);
+		logdebugx("RA for unexpected interface from %s", sfrom);
 #endif
 		return;
 	}
 
 	if (len < sizeof(struct nd_router_advert)) {
-		logerrx("IPv6 RA packet too short from %s", ctx->sfrom);
+		logerrx("IPv6 RA packet too short from %s", sfrom);
 		return;
 	}
 
 	/* RFC 4861 7.1.2 */
 	if (hoplimit != 255) {
-		logerrx("invalid hoplimit(%d) in RA from %s",
-		    hoplimit, ctx->sfrom);
+		logerrx("invalid hoplimit(%d) in RA from %s", hoplimit, sfrom);
 		return;
 	}
-
-	if (!IN6_IS_ADDR_LINKLOCAL(&ctx->from.sin6_addr)) {
-		logerrx("RA from non local address %s", ctx->sfrom);
+	if (!IN6_IS_ADDR_LINKLOCAL(&from->sin6_addr)) {
+		logerrx("RA from non local address %s", sfrom);
 		return;
 	}
 
 	if (!(ifp->options->options & DHCPCD_IPV6RS)) {
 #ifdef DEBUG_RS
-		logerrx("%s: unexpected RA from %s",
-		    ifp->name, ctx->sfrom);
+		logerrx("%s: unexpected RA from %s", ifp->name, sfrom);
 #endif
 		return;
 	}
@@ -930,20 +927,20 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 	if (ipv6_linklocal(ifp) == NULL) {
 #ifdef DEBUG_RS
 		logdebugx("%s: received RA from %s (no link-local)",
-		    ifp->name, ctx->sfrom);
+		    ifp->name, sfrom);
 #endif
 		return;
 	}
 
-	if (ipv6_iffindaddr(ifp, &ctx->from.sin6_addr, IN6_IFF_TENTATIVE)) {
+	if (ipv6_iffindaddr(ifp, &from->sin6_addr, IN6_IFF_TENTATIVE)) {
 		logdebugx("%s: ignoring RA from ourself %s",
-		    ifp->name, ctx->sfrom);
+		    ifp->name, sfrom);
 		return;
 	}
 
 	TAILQ_FOREACH(rap, ctx->ra_routers, next) {
 		if (ifp == rap->iface &&
-		    IN6_ARE_ADDR_EQUAL(&rap->from, &ctx->from.sin6_addr))
+		    IN6_ARE_ADDR_EQUAL(&rap->from, &from->sin6_addr))
 			break;
 	}
 
@@ -968,8 +965,8 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 			return;
 		}
 		rap->iface = ifp;
-		rap->from = ctx->from.sin6_addr;
-		strlcpy(rap->sfrom, ctx->sfrom, sizeof(rap->sfrom));
+		rap->from = from->sin6_addr;
+		strlcpy(rap->sfrom, sfrom, sizeof(rap->sfrom));
 		TAILQ_INIT(&rap->addrs);
 		new_rap = true;
 	} else
@@ -991,8 +988,7 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 	 * in accordance with the own prefix times which would result in too
 	 * much needless log spam. */
 	logfunc = new_rap ? loginfox : logdebugx,
-	logfunc("%s: Router Advertisement from %s",
-	    ifp->name, ctx->sfrom);
+	logfunc("%s: Router Advertisement from %s", ifp->name, rap->sfrom);
 
 	clock_gettime(CLOCK_MONOTONIC, &rap->acquired);
 	rap->flags = nd_ra->nd_ra_flags_reserved;
@@ -1053,10 +1049,10 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 			}
 			if (dho != NULL)
 				logwarnx("%s: reject RA (option %s) from %s",
-				    ifp->name, dho->var, ctx->sfrom);
+				    ifp->name, dho->var, rap->sfrom);
 			else
 				logwarnx("%s: reject RA (option %d) from %s",
-				    ifp->name, ndo.nd_opt_type, ctx->sfrom);
+				    ifp->name, ndo.nd_opt_type, rap->sfrom);
 			if (new_rap)
 				ipv6nd_removefreedrop_ra(rap, 0, 0);
 			else
@@ -1196,7 +1192,7 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx, struct interface *ifp,
 		    dho->option))
 		{
 			logwarnx("%s: reject RA (no option %s) from %s",
-			    ifp->name, dho->var, ctx->sfrom);
+			    ifp->name, dho->var, rap->sfrom);
 			if (new_rap)
 				ipv6nd_removefreedrop_ra(rap, 0, 0);
 			else
@@ -1584,8 +1580,8 @@ ipv6nd_drop(struct interface *ifp)
 }
 
 static void
-ipv6nd_handlena(struct dhcpcd_ctx *ctx, struct interface *ifp,
-    struct icmp6_hdr *icp, size_t len, int hoplimit)
+ipv6nd_handlena(struct dhcpcd_ctx *ctx, const char *sfrom,
+    struct interface *ifp, struct icmp6_hdr *icp, size_t len, int hoplimit)
 {
 	struct nd_neighbor_advert *nd_na;
 	struct in6_addr nd_na_target;
@@ -1596,22 +1592,20 @@ ipv6nd_handlena(struct dhcpcd_ctx *ctx, struct interface *ifp,
 
 	if (ifp == NULL) {
 #ifdef DEBUG_NS
-		logdebugx("NA for unexpected interface from %s",
-		    ctx->sfrom);
+		logdebugx("NA for unexpected interface from %s", sfrom);
 #endif
 		return;
 	}
 
 	if ((size_t)len < sizeof(struct nd_neighbor_advert)) {
-		logerrx("%s: IPv6 NA too short from %s",
-		    ifp->name, ctx->sfrom);
+		logerrx("%s: IPv6 NA too short from %s", ifp->name, sfrom);
 		return;
 	}
 
 	/* RFC 4861 7.1.2 */
 	if (hoplimit != 255) {
 		logerrx("invalid hoplimit(%d) in NA from %s",
-		    hoplimit, ctx->sfrom);
+		    hoplimit, sfrom);
 		return;
 	}
 
@@ -1625,7 +1619,7 @@ ipv6nd_handlena(struct dhcpcd_ctx *ctx, struct interface *ifp,
 	memcpy(&nd_na_target, &nd_na->nd_na_target, sizeof(nd_na_target));
 	if (IN6_IS_ADDR_MULTICAST(&nd_na_target)) {
 		logerrx("%s: NA multicast address %s (%s)",
-		    ifp->name, taddr, ctx->sfrom);
+		    ifp->name, taddr, sfrom);
 		return;
 	}
 
@@ -1637,20 +1631,20 @@ ipv6nd_handlena(struct dhcpcd_ctx *ctx, struct interface *ifp,
 	if (rap == NULL) {
 #ifdef DEBUG_NS
 		logdebugx("%s: unexpected NA from %s for %s",
-		    ifp->name, ctx->sfrom, taddr);
+		    ifp->name, sfrom, taddr);
 #endif
 		return;
 	}
 
 #ifdef DEBUG_NS
 	logdebugx("%s: %sNA for %s from %s",
-	    ifp->name, is_solicited ? "solicited " : "", taddr, ctx->sfrom);
+	    ifp->name, is_solicited ? "solicited " : "", taddr, sfrom);
 #endif
 
 	/* Node is no longer a router, so remove it from consideration */
 	if (!is_router && !rap->expired) {
 		loginfox("%s: %s not a router (%s)",
-		    ifp->name, taddr, ctx->sfrom);
+		    ifp->name, taddr, sfrom);
 		rap->expired = 1;
 		rt_build(ifp->ctx,  AF_INET6);
 		script_runreason(ifp, "ROUTERADVERT");
@@ -1665,33 +1659,43 @@ static void
 ipv6nd_handledata(void *arg)
 {
 	struct dhcpcd_ctx *ctx;
+	struct sockaddr_in6 from;
+	unsigned char buf[64 * 1024]; /* Maximum ICMPv6 size */
+	struct iovec iov = {
+		.iov_base = buf,
+		.iov_len = sizeof(buf),
+	};
+	unsigned char ctl[CMSG_SPACE(sizeof(struct in6_pktinfo)) + CMSG_SPACE(sizeof(int))] = { 0 };
+	struct msghdr msg = {
+	    .msg_name = &from, .msg_namelen = sizeof(from),
+	    .msg_iov = &iov, .msg_iovlen = 1,
+	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	};
 	ssize_t len;
 	struct cmsghdr *cm;
+	char sfrom[INET6_ADDRSTRLEN];
 	int hoplimit;
 	struct in6_pktinfo pkt;
 	struct icmp6_hdr *icp;
 	struct interface *ifp;
 
 	ctx = arg;
-	ctx->rcvhdr.msg_controllen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
-	    CMSG_SPACE(sizeof(int));
-	len = recvmsg_realloc(ctx->nd_fd, &ctx->rcvhdr, 0);
+	len = recvmsg(ctx->nd_fd, &msg, 0);
 	if (len == -1) {
 		logerr(__func__);
 		return;
 	}
-	ctx->sfrom = inet_ntop(AF_INET6, &ctx->from.sin6_addr,
-	    ctx->ntopbuf, INET6_ADDRSTRLEN);
+	inet_ntop(AF_INET6, &from.sin6_addr, sfrom, sizeof(sfrom));
 	if ((size_t)len < sizeof(struct icmp6_hdr)) {
-		logerrx("IPv6 ICMP packet too short from %s", ctx->sfrom);
+		logerrx("IPv6 ICMP packet too short from %s", sfrom);
 		return;
 	}
 
 	pkt.ipi6_ifindex = 0;
 	hoplimit = 0;
-	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&ctx->rcvhdr);
+	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&msg);
 	     cm;
-	     cm = (struct cmsghdr *)CMSG_NXTHDR(&ctx->rcvhdr, cm))
+	     cm = (struct cmsghdr *)CMSG_NXTHDR(&msg, cm))
 	{
 		if (cm->cmsg_level != IPPROTO_IPV6)
 			continue;
@@ -1708,7 +1712,7 @@ ipv6nd_handledata(void *arg)
 	}
 
 	if (pkt.ipi6_ifindex == 0) {
-		logerrx("IPv6 RA/NA did not contain index from %s", ctx->sfrom);
+		logerrx("IPv6 RA/NA did not contain index from %s", sfrom);
 		return;
 	}
 
@@ -1724,22 +1728,22 @@ ipv6nd_handledata(void *arg)
 	    !(ifp->options->options & DHCPCD_IPV6)))
 		return;
 
-	icp = (struct icmp6_hdr *)ctx->rcvhdr.msg_iov[0].iov_base;
+	icp = (struct icmp6_hdr *)buf;
 	if (icp->icmp6_code == 0) {
 		switch(icp->icmp6_type) {
 			case ND_NEIGHBOR_ADVERT:
-				ipv6nd_handlena(ctx, ifp, icp, (size_t)len,
-				   hoplimit);
+				ipv6nd_handlena(ctx, sfrom,
+				    ifp, icp, (size_t)len, hoplimit);
 				return;
 			case ND_ROUTER_ADVERT:
-				ipv6nd_handlera(ctx, ifp, icp, (size_t)len,
-				   hoplimit);
+				ipv6nd_handlera(ctx, &from, sfrom,
+				    ifp, icp, (size_t)len, hoplimit);
 				return;
 		}
 	}
 
 	logerrx("invalid IPv6 type %d or code %d from %s",
-	    icp->icmp6_type, icp->icmp6_code, ctx->sfrom);
+	    icp->icmp6_type, icp->icmp6_code, sfrom);
 }
 
 static void